Before being lucky enough to score my K1, I read/heard many reviews about the DIM screen and up until recently I had bought into the notion that the screen was good, but not as bright. I have had many androids and like most people with an android phone I realized that the adaptive brightness often skewed the perception of how bright the screen really is.
If you feel that your screen isnt as bright -- try turning off adaptive brightness in settings and I think you'll be much happier. Of course this will impact battery life, but c'mon who doesnt charge their phone every night anyways?